Hospitals and respiratory therapists administer treating gases to individual patients by placing a respiratory mask over the patient's nose and mouth. The masks are supplied in standard sizes intended for adults and children. However, many adult patients have smaller facial dimensions such that the standard sizes do not fit properly, at best making the mask uncomfortable and at worst leading to ineffective administration of treating gases. In addition, many children have smaller facial dimensions such that the standard mask sizes provided for children do not fit them. Hence, an adjustable-size respiratory mask is needed to fit patients with smaller facial dimensions.
U.S. Pat. No. 4,657,010 discloses an adjustable face mask in which the bottom of the mask may be extended lengthwise by fastening a separate extension portion (lower portion 14) to the mask. The lower portion 14 is provided with snap closures 42 that mate with eyelet holes 40 in the upper portion of the mask. The separate extension portion is awkward, and size adjustments can not effectively be made while the mask is in place over a patient's face. Most patient discomfort is caused when a too large size mask covers their eyes and/or forehead, making the bottom portion size adjustment in this prior patent less helpful when trying to solve the problems associated with over-sized respiratory masks. Moreover, the separate extension portion is more apt to be disconnected or lost before or during use.